The present invention relates to catalyst activator compositions, to methods of making these activator compositions, to polymerization catalyst systems containing these activator compositions, and to olefin(s) polymerization processes utilizing same. More specifically, the present application relates to the preparation and use of carbonium salt complexes containing at least one anionic aluminum, to catalyst systems containing these complexes, and to polymerization processes utilizing same.
Polymerization catalyst compounds, including bulky ligand metallocene catalyst compounds, are typically combined with an activator (or co-catalyst) to yield compositions having a vacant coordination site that will coordinate, insert, and polymerize olefins. Known activators included alumoxane, modified alumoxanes, aluminum alkyls, and ionizing activators. Examples of neutral ionizing activators include Group 13 based Lewis acids having three fluorinated aryl substituents, and examples of ionic ionizing activators include ammonium cations or trityl cations (triphenylcarbenium) combined with noncoordinating/weakly coordinating borate or aluminate anions.
Alumoxane activators are generally oligomeric compounds containing xe2x80x94Al(R)xe2x80x94Oxe2x80x94 subunits, where R is an alkyl group. Examples of alumoxanes include methylalumoxane (MAO), modified methylalumoxane (MMAO), ethylalumoxane and isobutylalumoxane. Alumoxanes may be produced by the hydrolysis of the respective trialkylaluminum compound. MMAO may be produced by the hydrolysis of trimethylaluminum and a higher trialkylaluminum such as triisobutylaluminum. MMAO""s are generally more soluble in aliphatic solvents and more stable during storage. A variety of methods for preparing alumoxanes and modified alumoxanes are described in U.S. Pat. Nos. 4,665,208, 4,952,540, 5,091,352, 5,206,199, 5,204,419, 4,874,734, 4,924,018, 4,908,463, 4,968,827, 5,308,815, 5,329,032, 5,248,801, 5,235,081, 5,157,137, 5,103,031, 5,391,793, 5,391,529, 5,693,838, 5,731,253, 5,731,451, 5,744,656, 5,847,177, 5,854,166, 5,856,256 and 5,939,346 and European publications EP-A-0 561 476, EP-B1-0 279 586, EP-A-0 594-218 and EP-B1-0 586 665, and PCT publication WO 94/10180. Known alumoxane activators are also disclosed in U.S. Pat. No. 5,041,584. Another known activator, modified methyl alumoxane in heptane (MMAO3A) is commercially available from Akzo Chemicals, Inc., Houston, Tex. Alumoxanes, however, must generally be present in a large excess over the catalyst compound to be effective activators, which significantly increases the costs of such catalyst systems.
Aluminum alkyl compounds, including trialkylaluminums and alkyl aluminum chlorides, are also known to be useful as activators. Examples of these compounds include trimethylaluminum, triethylaluminum, triisobutylaluminum, tri-n-hexylaluminum, tri-n-octylaluminum and the like.
Neutral ionizing activators include Group 13 based Lewis acids, having three fluorinated aryl substituents, are capable of activating olefin polymerization catalysts. Specific examples of these activators include trisperfluorophenyl boron and trisperfluoronapthyl boron. Trisperfluorophenylborane, is demonstrated in EP-A1-0 425 697 A1 and EP-B1-0 520 732 to be capable of abstracting a ligand for cyclopentadienyl derivatives of transition metals while providing a stabilizing, compatible noncoordinating anion. See also, Marks, et al, J. Am. Chem. Soc. 1991, 113, 3623-3625. The noncoordinating anions are described to function as electronic stabilizing cocatalysts, or counterions, for cationic metallocene complexes which are active for olefin polymerization. The term noncoordinating anion as used herein applies to noncoordinating anions and coordinating anions that are at most weakly coordinated to the cationic complex so as to be labile to replacement by olefinically or acetylenically unsaturated monomers at the insertion site. The synthesis of Group 13-based compounds derived from trisperfluorophenylborane are described in EP 0 694 548 A1. These Group 13-based compounds are said to be represented by the formula M(C6F5)3 and are prepared by reacting the trisperfluorophenylborane with dialkyl or trialkyl Group 13-based compounds at a molar ratio of about 1:1 so as to avoid mixed products, those including the type represented by the formula M(C6F5)nR3xe2x88x92n, where n=1 or 2. Utility for the tris-aryl aluminum compounds in Ziegler-Natta olefin polymerization is suggested.
Ionizing ionic activators, for example, include ammonium cations, such as N,N-dimethylanilinium, or trityl cations (triphenylcarbenium or trityl+) combined with noncoordinating/weakly coordinating borate or aluminate anions, such as, for example tetra(perfluorophenyl)borate. Such compounds and the like are described in European publications EP-A-0 570 982, EP-A-0 520 732, EP-A-0 495 375, EP-B1-0 500 944, EP-A-0 277 003 and EP-A-0 277 004, and U.S. Pat. Nos. 5,153,157, 5,198,401, 5,066,741, 5,206,197, 5,241,025, 5,384,299, 5,447,895 and 5,502,124 and U.S. patent application Ser. No. 08/285,380, filed Aug. 3, 1994, all of which are fully incorporated herein by reference.
Perfluorophenyl-aluminum complexes, however, have been implicated as possible deactivation sources in olefin polymerizations which utilize Trityl+ B(C6F5)4xe2x88x92/alkylaluminum combinations to activate the catalysts. See, Bochmann, M.; Sarsfield, M. J.; Organometallics 1998, 17, 5908. Perfluorophenylaluminum (toluene), for example, has been characterized via X-ray crystallography. See, Hair, G. S., Cowley, A. H., Jones, R. A., McBurnett, B. G.; Voigt, A., J. Am. Chem. Soc., 1999, 121, 4922. Arene coordination to the aluminum complex demonstrates the Lewis acidity of the aluminum center. Bochmann and Sarsfield have shown that Cp2ZrMe2 reacts with Al(C6F5)30.5(toluene) with transfer of the C6F5xe2x88x92 moiety forming metallocene pentafluorophenyl complexes. These complexes, however, were reported having very low activity compared to the corresponding metallocene dimethyl complexes when activated with B(C6F5)3 or Trityl+ B(C6F5)4xe2x88x92.
The supporting of ionic activators, however, typically results in a significant loss of activity. Supported non-coordinating anions derived from trisperfluorophenyl boron are described in U.S. Pat. No. 5,427,991. Trisperfluorophenyl boron is shown to be capable of reacting with coupling groups bound to silica through hydroxyl groups to form support bound anionic activators capable of activating transition metal catalyst compounds by protonation. U.S. Pat. Nos. 5,643,847 and 5,972,823 discuss the reaction of Group 13 Lewis acid compounds with metal oxides such as silica and illustrate the reaction of trisperfluorophenyl boron with silanol groups (the hydroxyl groups of silicon) resulting in bound anions capable of protonating transition metal organometallic catalyst compounds to form catalytically active cations counter-balanced by the bound anions.
Immobilized Group IIIA Lewis acid catalysts suitable for carbocationic polymerizations are described in U.S. Pat. No. 5,288,677. These Group IIIA Lewis acids are said to have the general formula RnMX3xe2x88x92n where M is a Group IIIA metal, R is a monovalent hydrocarbon radical consisting of C1 to C12 alkyl, aryl, alkylaryl, arylalkyl and cycloalkyl radicals, n=0 to 3, and X is halogen. Listed Lewis acids include aluminum trichloride, trialkyl aluminums, and alkylaluminum halides. Immobilization is accomplished by reacting these Lewis acids with hydroxyl, halide, amine, alkoxy, secondary alkyl amine, and other groups, where the groups are structurally incorporated in a polymeric chain. James C. W. Chien, Jour. Poly. Sci.: Pt A: Poly. Chem, Vol. 29, 1603-1607 (1991), describes the olefin polymerization utility of methylalumoxane (MAO) reacted with SiO2 and zirconocenes and describes a covalent bonding of the aluminum atom to the silica through an oxygen atom in the surface hydroxyl groups of the silica.
Additional compounds useful as activators also include those described in PCT publications WO 98/07515, which discloses tris (2,2xe2x80x2,2xe2x80x3-nonafluorobiphenyl) fluoroaluminate, WO 98/09996, which describes activating bulky ligand metallocene catalyst compounds with perchlorates, periodates and iodates including their hydrates, WO 98/30602 and WO 98/30603, which describe the use of lithium (2,2xe2x80x2-bisphenyl-ditrimethylsilicate).4THF as an activator for a bulky ligand metallocene catalyst compound, WO 99/18135 which describes the use of organo-boron-aluminum activators, and in EP-B1-0 781 299 which describes using a silylium salt in combination with a non-coordinating compatible anion, all of which are herein fully incorporated by reference. Further activators or methods for activating a bulky ligand metallocene catalyst compound are described in for example, U.S. Pat. Nos. 5,849,852, 5,859,653 and 5,869,723 and WO 98/32775, WO 99/42467 (dioctadecylmethylammonium-bis(tris(pentafluorophenyl) borane)benzimidazolide), which are also fully incorporated herein by reference.
U.S. Pat. No. 5,895,771 discloses a catalyst composition comprising a neutral metallocene and an anionic aluminum containing complex which is a fluorinated alkoxy and/or arylalkoxy aluminate where the fluorinated alkoxy aluminate can be of the formula A+(Al(OR)4)xe2x88x92.
Harney, D. W et al., Aust. J. Chem. (1974) 27, 1639, discuss the reaction of triphenylmethanol and trimethylaluminum. Water is reported to catalyze the formation of 1,1,1-triphenylethane from the reaction of trimethylaluminum and [Me2AlOC(C6H5)3]2.
WO 99/15534 reports the reaction of methylalumoxane and tris-pentafluorophenylaluminum.
WO 99/06414 reports compounds of the formula [R2Bxe2x80x94Xxe2x80x94AlR,R]x.
While these catalyst activator compounds have been described in the art, there is still a need for improved catalyst activators, for activators suitably for anchoring on supports, and for catalyst systems utilizing such activators.
This invention provides new polymerization catalyst activator compositions including a carbonium cation and an aluminum containing anion. These activator compositions are prepared by combining a carbonium or trityl source and with an aluminum containing complex, preferably a perfluorophenylaluminum compound. The invention also provides for methods of making the activator compositions of the invention, a polymerization catalyst system which includes the activator composition of the invention, and a process for polymerizing olefins utilizing same.